iMONITOR
Silent Key
How is the AR-DV1 with regards to intermod? When monitoring VHF aircraft has anyone found it necessary or recomended the use of notch filters for the U.S. FM broadcast band and pager frequencies?
AR-DV1 Notch Filters needed with the AR-DV1? ie; Pager Intermod/FM Broadcast (88-108MHz)
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I always have a FM notch filter inline no matter what band I am monitoring. I live in a highly broadcast radio saturated area it pretty much helps all around but especially on the air band. If you haven't already grab a notch filter from PAR Electronics. They works great and are built to survive the apocalypse, I honestly have never seen a more solid hobby level filter. Anyway just my opinion I am sure there will be others.
iMONITOR
Silent Key
I'm familiar with PAR's FM 88-108MHz notch filter. I've had them in the past and like I so often do I sold it when I was done with it only to buy one again. You are correct in that they're made very well and work perfect. I'm just not sure the AR-DV1 would actually need one.
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I can say that while an in-line FM broadcast filter is usually a good idea all around, the AOR DV-1 has not exhibited any issues with intermod in some pretty RF saturated areas I've taken it, at least so far...
Chris
Chris
hamradionl
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Dale from PAR Electronics, dont take orders due the are busy large order.
Ubbe
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Long before intermod appears you get de-sense of the receiver. A strong signal works as a threshold or knee that the signal needs to overcome to get past the first amplifier in the receiver. If you receive everything you need and don't get intermod then you don't need additional filters. But if you need to monitor weak signals in VHF and LO-VHF then you probably need a FM broadcast filter to hear everything you should hear.
I wouldn't expect the UHF filters in a receiver being so bad that you'll need to use a 88-108MHz band stop filter. If you see a difference in UHF it probably are because the FM filter also attenuates UHF signals a couple of dB's and you where suffering from strong signal de-sense. A good FM trap filter, that doesn't attenuate the lower part of the airband, and an adjustable attenuator are always good to have when dealing with external antennas when checking if additional filtering are neccesary.
/Ubbe
I wouldn't expect the UHF filters in a receiver being so bad that you'll need to use a 88-108MHz band stop filter. If you see a difference in UHF it probably are because the FM filter also attenuates UHF signals a couple of dB's and you where suffering from strong signal de-sense. A good FM trap filter, that doesn't attenuate the lower part of the airband, and an adjustable attenuator are always good to have when dealing with external antennas when checking if additional filtering are neccesary.
/Ubbe
iMONITOR
Silent Key
Par must have caught up with that large order. I ordered an FM notch filter from Universal Radio and they had to back order it. However about 2-1/2 weeks later it was in my mail box. It was bakery fresh, I could actually smell the new paint on it from a very recent production run!
Not to get off-topic, but I've received several of the fresh paint smell ones from Dale as well. At least we know it isn't old stock.
hamradionl
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I talk to Par yesterday, i will ask again.
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I always use an FM broadcast notch filter no matter what receiver--Scanner, AirSpy, R8600, and even an R9500. With a pre-amp, it is a must. Besides de-sense near the band, a too strong signal into a pre-amp will be an invitation for intermod products to show up throughout the spectrum. I use a Mini-Circuits one as after testing all that I could find, it was the best.
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